I think this isn’t really free transport’s fault, this is a problem with youths being antisocial, it has different causes. The free bus just helps to make it more concentrated in certain places, but the solution isnt to make the bus paid but to help the youth find better things to do.

Also to quote the first article

Despite its success, First Bus, Scotland’s largest bus operator, confirmed to The Herald it has experienced “a slight increase” in youth disorder on its network of routes since the scheme was launched, although it added that the rise “cannot be directly attributed” to the roll-out of the scheme.